Two of the five light bulbs in my handlebar grips were burned out. As part of my quest to replace every light bulb on my bike with an LED, I pulled the grips apart and put blue LEDs in to replace the light bulbs in there. The light bulbs are absolutely tiny:

I'm quite pleased with the result:

It looks a bit brighter in the picture than they actually are, because of the exposure I used - I wanted to make sure you could tell in the picture that they were lit up. They actually appear just about the same as the original light bulbs.